The 366 is a technically a big block as it shares the same stroke/engine design of the other GM other big block engines. So I am not worried about 3700 rpm too much. Cruising on the highway 3300rmp would put the bus at 73% of it's redline, where 3700 puts it at 82%. 4000 is a tad high for my liking at 89% of maximum engine rpm.
Fuel economy to me isn't an issue, it will cost what it will cost to get me there
My time/safety is worth more than the $50 more it might cost me on a trip.
That being said...
I have decided just to make a toggle switch that can connect the wires if I really
have to bump the rpm, but in the meantime I am now convinced that my power issue was more tune-up related than top-end rpm related.